If you take asthma medication, you probably are familiar with inhalers. They seem like simple devices. But if you don't use them correctly, you may not get enough medicine where it needs to go - deep inside your lungs. That can keep you from getting the right amount of the medicine, making your asthma worse instead of better.

What is a metered-dose inhaler?Metered-dose inhalers are built to release a measured amount of medicine each time you squeeze them. They have a canister that keeps the medicine pressurized, and a sleeve that you place in or near your mouth. Most people with asthma use a metered-dose inhaler for both long-term control medication and quick-relief treatment.

How to use a metered-dose inhalerSince it can be difficult to use an inhaler the right way, ask your doctor, nurse or pharmacist to show you how. Make sure you know how to hold it and when to breathe. Not all inhalers are used the same way.

Follow these general tips:

Read your inhaler's instructions on priming and cleaning the device.

To start, take off the cap that covers the mouthpiece and look inside to make sure nothing is blocking it.

Hold upright and shake the inhaler.

Stand up or sit up straight and take a deep breath in and then breathe out.

Follow your doctor's instructions to have the inhaler in your mouth, held away from your mouth or use a spacer.

As you start to inhale, push down on the top of the canister. Breathe in slowly as deeply as you can. Keep breathing in slowly for at least 3 to 5 seconds.

Hold your breath for 10 seconds if you can. Breathe out.

If your doctor has told you to use two puffs of medicine, repeat steps 1 to 7 for the second puff.

If you are using a corticosteroid, rinse your mouth out and spit. This will help prevent thrush.

Each time you visit your doctor, ask for a refresher course on how to use the inhaler.

Ways to avoid getting too little medicineIf you feel the inhaler is not helping as much as it should be, there may be an easy fix. Make sure you:

Take the cap off the inhaler before using it.

Breathe slowly and deeply when you press on the canister.

Breathe in through your mouth, not your nose.

Make sure your inhaler isn't empty.

Talk to your doctor about using a spacer.

What is a spacer?A spacer is a plastic tube that attaches to your inhaler. It is designed to help the medicine bypass your mouth and throat and get into your lungs. It can help you avoid common problems, like breathing in at the wrong time or breathing in too fast. It may also make you less susceptible to the mouth infection called thrush - a side effect of inhaled corticosteroid medicine, which is a medication in some inhalers.

One type of spacer is called a valved holding chamber. It has a valve at the mouthpiece, so you can't accidentally breathe out into the tube. The chamber holds the medicine until you are ready to inhale slowly and deeply.

Your doctor can help you choose which type of device is best for you. Both children and adults can benefit from using a spacer.

When does an inhaler need to be replaced?Keep track of how often you use your inhaler. When you pick up your medicine, discuss when you will need to replace it with your pharmacist.

It may seem that shaking your inhaler will tell you whether it's empty or not. But what you hear inside may just be propellant, not medicine.

Some inhalers have a dose counter that indicates how much has been used. Or you can look at the instructions and find out how many puffs it contains.

In the past, you may have been told to drop your inhaler in water and see if it floats. This was thought to show you if it was empty. That is no longer suggested as a way to find out if you need to replace your inhaler. It is not reliable. Counting puffs as explained above or talking to your pharmacist are the best ways to know when to replace your inhaler.

By Emily Gurnon, Contributing WriterCreated on 11/26/2001Updated on 06/06/2013

Sources:

National Heart, Lung, and Blood Institute. Asthma and physical activity in the school.

National Heart, Lung, and Blood Institute. How is asthma treated and controlled?